1. Field of the Invention
The present invention relates to an apparatus for processing an image signal, and more particularly, to an image signal processing apparatus and method capable of easily performing format conversion and image quality improvement of an image signal inputted from an external device. The present application is based on Korean Patent Application No. 2001-65597, filed Oct. 24, 2001, which is incorporated herein by reference.
2. Description of the Related Art
A television set (TV) is a typical apparatus for displaying an image signal. The typical TV outputs images, by use of a Braun tube (cathode ray tube). Such a TV using a cathode ray tube has drawbacks of high power consumption and large volume. Accordingly, the above drawbacks brought about the use of a liquid crystal TV using a LCD, a plasma TV using a plasma display, or the like. A liquid crystal or plasma TV is an improvement of the conventional Braun tube in an attempt to solve the drawbacks of the conventional Braun tube, such as high power consumption and large volume. Because of the high price of the liquid crystal or plasma TV, however, Braun tubes are widely used at the present.
In the development of a new display appliance, there also have been many efforts to increase the width of the display device. As a broadcasting station transmits a broadcasting signal of a constant size, a technique of format-converting the constant size of the broadcasting signal into a signal having a size suitable for the widened screen is required.
In addition, in accordance with the increased use of personal computers, recently, it is also demanded that an output screen of the computer is displayed on a home TV or LCD monitor. In this case, since a scanning line of the LCD monitor or TV is not identical with that of the personal computer, it is impossible to output various kinds of video formats (SVGA, XGA and VGA) inputted from the personal computer on the TV or LCD monitor as they are. Accordingly, the various kinds of image signals to be inputted must be format-converted appropriately for the display appliance.
FIG. 1 is a block diagram perspectively illustrating an image signal processing apparatus of the prior art. The apparatus comprises a format converting section 100 for converting a format of an image signal inputted from an external device, such as a TV broadcasting signal, a video signal, a DVD signal or the like, into a format corresponding to the size of a TV screen, and an image quality improving section 110 for improving the image signal outputted from the format converting section 100 by use of an algorithm such as noise reduction, profile emphasize, contrast enhancement or the like.
According to the prior art apparatus, a plurality of image signals inputted to the format converting section 100 are regarded as a broadcasting signal generally received by the TV, and resolution, a size of the screen, a frequency of an image and the like are converted to be displayed on the display appliance.
In addition, the prior art apparatus has no consideration for the characteristic of the inputted image signals relative to each image signal such as a video signal, a TV broadcasting signal, a camcorder signal, and a DVD image signal. Accordingly, since the inputted image signal is regarded as the same signal as the TV broadcasting signal, the process of format conversion and quality improvement is implemented by the same method as that of the TV broadcasting signal. Therefore, there is a problem that since all the image signals are processed according to the same pattern, the characteristics of the respective image signal are not maintained.